Impact tools

ABSTRACT

Manual and pneumatically operated impact tools for driving fasteners into concrete through the utilization of the kinetic energy of a hammer impacting a driver. The tools are adapted to insure the perpendicularity of the fasteners and to drive the fasteners in close proximity to a wall or vertical surface.

United States Patent [191 Clifford et al. 1 Jan. 16, 1973 1541 IMPACT TOOLS 2,557,000 6/195] Holmes ..227 147 x 3,060,440 10/1962 Pfaff et al. ..227 147 [76] lnvemors- 23 Fwy Acres 3,060,441 10/1962 Henning ..227 147 Dflve, Wayland, Mass- 01778; 3,498,517 3 1970 Novak ..227 130 x Harry M. Haytayan, Sunnside Lane, 3,595,460 7/l97l Pitkin ....227/l30 X Lincoln, Mass. 01773 3,570,738 3/1971 Pabich ..227 120 X Filed: Aug. 31, 1970 Appl. No.: 68,423

US. Cl ..227/147, 227/130 Int. Cl .;.B25c 7/00 Field of Search ..227/129, 130, 140, 147

References Cited UNITED STATES PATENTS 5/1962 Goldring ..227/130 X Primary ExaminerGranville Y. Custer, Jr. Attorney-Donald F. Daley [57] ABSTRACT Manual and pneumatically operated impact tools for driving fasteners into concrete through the utilization of the kinetic energy of a hammer impacting a driver. The tools are adapted to insure the perpendicularity of the fasteners and to drive the fasteners in close proximity to a wall or vertical surface.

2 Claims, 6 Drawing Figures PATENTEDJAM 16 ms 3. 711 008 I SHEET 3 0F 3 INVENTOR. HA RR y m HAYTAYA M ND PAUL CLIFFOED IMPACT TOOLS BACKGROUND OF THE INVENTION The present invention relates generally to impact tools for driving fasteners and the like, and specifically to manually and pneumatically operated impact tools for driving fasteners into concrete or other masonry surfaces.

Though the present invention is specifically intended to drive fasteners into concrete or hard, brittle surfaces, it is usable in driving fasteners into wood or other structural material. Nail or fastener driving devices are well known for applications such as laying hardwood flooring where nails are driven through wood boards into a wood subflooring. The impact tools used for this type of application usually consist of large bulky devices which are not suited for driving nails into concrete or hard, brittle surfaces.

Conventional nailing machines utilize a brute force technique where the piston area is made large enough to generate the necessary force to drive the nail into the woodpiece. The present invention utilizes not only the force generated by the action of the high pressure air on the piston, but it also utilizes the kinetic energy of the piston. This kinetic energy is generated by allowing .the piston to pick up velocity before it contacts the driver.

The present invention is particularly adapted for use in the installation of the small wooden strips used to hold wall to wall carpetingto concrete. Wall to wall carpeting is normally held in place by 1 wide and A" thick strips of wood secured to the flooring near the wall. These strips of wood have small tacks extending upward to grip the carpet and must be mounted very close to the wall or baseboard. Normally they are mounted A from the wall. The means presently used to install this stripping are explosive guns and manual hammers. The explosive technique is costly because of the cartridge expense and loading time required after every nail insertion. The manual technique is also costly because it requires the services of a skilled operator and is slow because of nailing accuracy requirements and the number of hammer blows required per nail. Skill is required to prevent or minimize damage to the baseboard or wall and chipping of the cement.

In order to use an automatic or manually operated impact device to secure the strip as close to the wall as possible, the impact device must be small in diameter, easily positionable and capable of positioning the strip without damaging the tacks or the wall or the baseboard. It should also be capable of automatically positioning the strip a specific distance from the wall and still drive the nail or fastener perpendicular to the flooring. These aspects are particularly important when the strips are to be secured to concrete flooring, since the nail should be driven with one blow and driven perpendicular to the floor so that the concrete does not chip and the nail does not bend.

It is therefore an object of the present invention to improve impact tools for driving fasteners or the like and to provide an impact tool which is relatively small in diameter and which will drive fasteners or nails into hard, brittle surfaces such as concrete with one sharp blow. It is a further objectof this invention to provide an impact tool for use in positioning and fastening wooden strips to concrete or other surfaces. It is a further object of this invention to provide an automatic impact tool which positions a nail perpendicular to a surface and drives the nail into the surface with one blow.

These and other objects of the invention are attained by meansof an impact tool having an automatic nail feeding and positioning device wherein a nail or fastener is positioned in close proximity to an anvil or driver which transmits the driving forcefrom a piston or hammer to the nail. The piston is mounted in a cylinder directly above the driver and movable into contact with the driver to provide the driving force. The movement of the piston is sufficient to produce the kinetic energy necessary to drive the nail into concrete or other hard surface. Means are provided to operate the piston manually or pneumatically.

For a better understanding of the invention as well a other objects and features thereof, reference is had to the following detailed description of the invention to be read in connection with the accompanying drawings, wherein:

FIG. 1 is an isometric view of a manually operated impact tool embodying the present invention.

FIG. 2 is a side view of the impact tool shown in FIG.

1, with portions broken away to internal structure.

FIG. 3 is an isometric view of a pneumatically operated impact tool embodying the present invention.

FIG. 4 is a side sectional view taken along lines 4-4 of FIG. 3.

FIG. 5 is an enlarged view ofa portion of FIG. 4.

FIG. 6 is a partial sectional view of the magazine" taken along lines 66 of FIG. 5.

FIG. 1 of the drawings shows a manually operated impact tool utilizing the present invention. A housing or main body 2 which provides the structural support for the impact mechanism is mounted above the driver housing 3 which includes positioning guides for a workpiece 6. The main body 2 and the driver housing 3 are shaped so that one outer surface 4 will fit flush with a wall or baseboard 1. When the workpiece 6 is wall to wall carpeting attachmentstrips, the workpiece is accurately positioned from the wall by means of the legs 5 on the bottom of the driver housing 3. The lower end of the driver housing 3 has a channel 8 extending therethrough parallel to the surface 4. The channel 8 is large enough to receive a workpiece 6 and has an edge guide 10 which gauges and positions the workpiece 6 relative to the surface 4.

Manual Impact Tool In order to drive a nail or fastener into the workpiece 6 there is shown in FIG. 2 an axially aligned nail slot 12 extending downward through a nail guide member 14. The length of guide member 14 is determined so that it contacts or is in close proximity with the surface through which the nail is to be driven. The length of the nail guide 14 and the depth and width of the channel 8 can be varied for specific specialized applications.

The slot 12 is sized to receive and guide a nail or fastener 18. Nails are fed from a spring-loaded cartridge or magazine 20 through a nail track 22 in the magazine to a positioning station which consists of an opening extending downward through the housing 3 into the slot 12. The slot 12 is rectangular shaped and the nail 18 has a teeshaped head so that the nail is held in place in the slot by the pressure exerted by nails being urged into the slot from a magazine. The tee shaped head allows passage of the nail through the slot 12 when impacted by a driver 30. The magazine 20 is attached to the housing 3 by appropriate fasteners, and may be of any type which automatically supplies nails to the slot 12 as each nail is driven into the workpiece 6.

Referring to FIG. 6, a cavity 17 in housing 3 contains a spring 19. The spring is attached to the housing 3 by a shoulder screw. A lever 21 is attached to the end of the spring 19 and is also connected to a plunger 23, seen in FIG. 6, that travels in the nail track 22. The plunger contacts the nails 18 in the track 22 and through the action of the spring indexes the nails automatically to the positioning station and slot 12 as each nail is driven into the workpiece 6. The nails may be bonded together for ease of loading. The lever 21 is easily removed from the nail track 22 by drawing the plunger 23 out of the magazine against the action of the spring. The length of the nail guide 14 and the depth and width of the channel 8 can be varied for specific specialized applications.

The driver housing 3 has a lower portion consisting of a workpiece guide channel 8 and four legs forming the channel 8. The legs 5 together with the magazine support leg 25 provide stability and perpendicularity for the entire tool. With the legs 5 and 25 resting on the surface into which a nail is to be driven, the nail will be perpendicular to the surface. The driver housing 3 has a driver guide track 28 extending downward through the housing to the nail slot 12. The guide track is sized and shaped to accommodate sliding movement of a driver 30. The driver 30 has an enlarged body portion 32 which mates with the guide track 28 for vertical. sliding movement. The lower end of the driver 30 has a reduced rectangular impact head 34 extending downward into the slot 12. The end of the impact head 34 is positioned slightly above .the head of a nail 18 positioned in the slot 12 when the driver is in an elevated position. When the driver is driven downward, the impact head contacts the nail in slot 12, driving it downward into the workpiece 6. Between the enlarged body portion 32 and the impact head 34 of the driver, there is a shoulder 36 positioned to engage a resilient bumper 37 to limit the downward movement of the driver. Above the enlarged body portion of the driver there is a drive head 38 extending upwards into the main housing 2.

The main housing 2 is tubular shaped with the interior of the tube adapted to receive and guide, for sliding movement, a hammer member 40. The hammer 40 consists of a rod shaped main body 42 sized for sliding movement within the upper portion of the housing 2, a hardened impact head 44 extending downward from the main body 42 to impact the drive head 38 of the driver, and a handle 46 secured to the upper portion of the main hammer body 42.

In operation, the impact tool is positioned over a workpiece by gripping the handle 46 and the main housing 2. The workpiece 6 is positioned by abutting the surface 4 of the housings 2 and 3 against a wall or baseboard. Raising the handle 46 elevates the hammer 40 within the tubular main housing 2 allowing a spring 50 in cavity 52 to urge the driver upwards until the enlarged body portion 32 of the driver contacts stop 54. The hammer is raised above the anvil a distance sufficient to permit enough kinetic energy to be developed when the hammer is moved downwards to drive a nail 18 into the workpiece and flooring. With the anvil in the elevated position, a nail 18 is indexed through the track 22 into the slot 12 by the spring 19 of the magazine 20. The hammer 40 is rapidly brought downward by movement of the handle 46 so that the impact head 44 of the hammer contacts the drive head 38 of the driver. The kinetic energy of the hammer is imparted to the driver 30 and the driver is driven downward with drive head 34 in contact with the nail 18 in slot 12. One sharp movement of the hammer is sufficient to drive the nail through the workpiece into concrete or masonry surface.

Pneumatic Impact Tool FIGS. 3 and 4 show a pneumatically operated fastener driving tool consisting of an upper housing member 102, a main housing 104, a driver housing 103, an air inlet assembly unit 106 and an actuating trigger 108. The driver housing 103 extends downward terminating in a workpiece positioning member of the same structure as that shown in FIGS. 1 and 2 and described relative to the manual impact tool. A cassette or magazine 112 is attached to the driver housing 103 and automatically provides nails or fasteners into the main housing 104 in the same manner previously described.

Within the main housing 104 there is a cylinder 1 14 which extends from the upper housing 102 downward to a point in the lower portion of the main housing 104 where it abuts a shoulder 116. The cylinder 114 is pneumatically sealed by an O ring positioned in a slot in the lower portion of the cylinder and bearing against the inner surface of the main housing 104.

Within the cylinder 114 there is a piston 126 adapted for movement throughout the length of the cylinder 1 14. Piston 126 consists of a main stem 128 which is of smaller diameter than the two ends of the piston 130 and 132. The ends of the piston 130 and 132 are sized for intimate sliding movement within the walls of the cylinder 114. The cylinder 114 has a larger internal diameter 134 in the upper portion of the cylinder and a smaller inner diameter 136 in the lower portion of the cylinder. The ends of the piston 130 and 132 are thus of different diameter with the upper portion of the piston 130 being larger than the lower portion 132. This difference in size between the two ends of the piston provides the differential force necessary to propel the piston upward when the tool is pneumatically energized. The piston 126 is pneumatically sealed within the cylinder 114 by means of a pair of 0 rings 138 and 139. The lower end of the piston 126 has a hammer or impact head 140 secured on the end thereof. In its lowermost position the impact head 140 rests on a resilient bumper I42 limiting the downward movement of the piston 126.

Referring to the upper housing 102, there is mounted therein an upper piston 144 having a pressure bearing surface 146, a guide stem 148 and a release vent 150 extending through the length of the piston 144. The guidestem 148 isfitted for movement within a bearing surface 152 within the housing 102 and is pneumatically sealed by means of an O ring 154. Upward movement of the piston 144 is limited by a resilient bumper 156 in the upper end of the guide cylinder 152. The lower or main portion of the piston 144 is sealed within a major cylinder 158 by means of a pair of rings 160 and 161. The lower portion of the upper piston has a resilient seal 162 which acts as a bumper and seal for the main piston 126 at the upper end of the main piston stroke. A chamber 164 is formed within the upper housing 102 by the cylinder 158 and the bearing surface 146 of the upper piston 144. The upper portion of piston 144 is larger than the lower portion of the same piston. Pneumatic pressure within the chamber 164 provides the differential force necessary to drive the piston 144 downward against the main cylinder 114 providing a seal for the upper end of the cylinder 114 and a stop for the main piston 126 in its upward movement.

Within the lower end of the main housing 104 there is a driver stem 170 extending upwards from an anvil or driver 171 and positioned within a small diameter cylinder 172 in the main housing 104. The anvil stem extends from a point wherein it will be contacted by the impact head 140 on the end of the piston 126 when the piston is in its lowermost position to a point immediately above the head of a nail or fastener 18 positioned within the impact tool at the positioning station. The anvil stem is surrounded by a compression spring 174 which bears against a retaining ring 176 in the anvil stem and a flange 178 located between the lower portion of the main housing 104 and the driver housing 103. Flange 178 also limits the upward movement of the driver 171. Downward movement of the piston 126 causes the impact head 140 to strike the upper end of the driver stem 170, which in turn imparts the force to the head of the nail or fastener 18.

The fastener supply assembly 112 and the positioning of the nails 18 and the workpiece 6 are the same as previously described for the manual impact tool. The driver housing 103 has legs which together with leg on the magazine 112 provide perpendicularity to the tool and nails. The surface 4 on the housings 103 and 104 provide alignment with a wall or baseboard and positioning of the workpiece 6 relative to the wall or baseboard.

Pneumatic System The pneumatic supply assembly 106 is mounted within a handle 200. The handle 200 is adapted for holding and positioning the impact tool and for coupling to a high pressure air source. The end of the handle 200 has the suitable connectors 202 for connection to an outside high pressure air source not shown. Air flows from the high pressure source into the handle wherein a high pressure reservoir chamber 204 is provided. Within the handle a ball valve assembly 206 is positioned to be actuated by the trigger 108. The ball valve assembly consists of a ball 208 mounted within a valve chamber 210. An actuating pin 212 extends from the trigger 108 upward through an opening 214 in the valve 206 into contact with the ball 208. High pressure air from the reservoir 204 flows through an opening 216 into the chamber 210 and exits through an opening 218. The high pressure forces the ball 208 downward within the chamber 210 against the resilient sealing ring 236 thus allowing the air to pass through the opening 216 into the chamber 210 and out the opening 218. Actuating the trigger 108 forces the rod 212 upward, which in turn forces the ball 208 upward against the resilient ring 220 surrounding the opening 216 and sealing off the opening 216. Release of the trigger 108 allows the air under pressure in reservoir 204 to force the ball 208 back downward, thus opening theflow of air through the opening 216 to the chamber 210 and out the opening 218. When the trigger is actuated and the ball 208 is forced against the opening 216 cutting off the air supply, the air in the chamber 210 and the passage 218 are vented to atmosphere through the opening 214 for the rod 212 by means of an air vent 222.

Operation In operation, the high pressure source is connected to the air inlet connectors 202 in the handle 200 of the impact tool. The air enters the reservoir 204 and passes through the passage 216 to the passage 218 of the valve assembly 206 and then through the passage 231. The air enters chamber 164 and forces the piston 144 down against cylinder 114. Simultaneously, the high pressure air enters the air accumulator 234 through a passage 230 in the main housing 104. The high pressure air then enters the main cylinder 114 through holes 238 and lifts the piston upward against the rubber seal 162 of the upper piston 144. A chamber 234 surrounds the cylinder 114 and extends upward to the lower portion of the upper housing 102. The chamber 234 is open to the top end of the cylinder 114 when the upper piston 144 is in the upward position. The upper piston 144 seals the cylinder 114 from the chamber 234 when it is in its downward position. At this time the anvil stem 170 is held in the raised position by the compression spring 174. In the pneumatic system, the vent port 222 of the valve body 206 is sealed off by the ball 208 being forced downward against a resilient sealing ring 236 surrounding the stem 212. The high pressure air in the chamber 164 above the upper piston forces the upper piston downward into the position shown in FIG. 2 sealing off the cylinder 114 from the accumulator chamber 234. The high pressure air in the accumulator passes through a series of openings 238 in the cylinder wall 114 into the chamber 240 formed by the undercut portion of the piston 126. The high pressure air in the chamber 240 causes the piston to move upward due to the difference in diameter of the upper portion of the piston 126 and the lower portion 132. Air within the cylinder 114 above the piston 126 is vented to atmosphere through the opening in the upper piston 144 and the air vent line 242 provided in the upper housing 102 to the guide cylinder 152. The downward or sealing movement of the upper piston 144 is achieved by means of the differential in the diameter of the upper piston exposed to the high pressure air in the chamber 164 and that exposed to the high pressure air in the cylinder 114 and the accumulator 234.

Actuation of the trigger 108 forces the rod 212 to move the valve ball 208 upward against the resilient member 220 in the opening 216. The ball 208 cuts off the high pressure air supply and vents the chamber 164 above the upper piston 144 through the passage 231, through 218, the valve chamber 210 and the air vent 222. The venting action of chamber 164 causes a differential in pressure between the upper portion of the upper cylinder 144 and the lower portion of the upper cylinder 144 that is exposed to the high pressure air of the accumulator 234. The unbalanced force generated causes the upper cylinder to move upwards, thus cutting off the vent 242 and exposing the top of the cylinder 1 14 to the high pressure air in the accumulator 234. The high pressure air in the accumulator 234 is then exposed to the top surface of the upper portion I30 of the piston I26. causing the piston 126 to move in a downward direction. This downward movement results from the difference in diameter between the upper portion 130 and the lower portion 132 of the piston 126. As the piston 126 moves to its downward position the impact head 140 contacts the anvil stem 170 which imparts the kinetic energy produced by the movement of the piston 126 to the head of the nail or fastener and drives it into the wood strip 6 and the concrete or masonry surface. The downward movement of the piston 126 is arrested by the resilient bumper 142.

Release of the trigger 108 allows the high pressure air to move the ball 208 downward within the chamber 210 against the resilient sealing ring 236 thus sealing off the vent 222 and energizing the impact tool for its next operation by moving the piston 126 upward and the upper piston 144 downward to the sealing position. The anvil stem is'returned to its uppermost position by means of the compression spring 174. A new nail or fastener is automatically inserted into position by the cassette or magazine and the operator merely moves the tool to the next position preparatory to actuating the trigger and driving another nail.

While the invention has been described with reference to the structures disclosed herein, it is not confined to the specific details set forth, since it is apparent that many modifications and changes can be made by those skilled in the art. This application is therefore intended to cover such modifications or changes as may come within the purposes of the improvements or scope of the following claims.

What is claimed is:

1. An impact tool for driving fasteners through a workpiece into masonry surfaces or the like including:

a driver housing having means to locate a workpiece in a position to receive a fastener above the workpiece and means to align the impact tool so that a fastener in the positioning station is substantially perpendicular to the surface into which the fastener is to be driven, including four leg members extending downward from the driver housing in a position to straddle the workpiece and a fifth leg member remote from the driver housing to provide stability;

a driver positioned in the driver housing immediately above the fastener positioning station and movable downward through the fastener positioning station; 1

means to impact the driver with a velocity sufficient to force the driver downward through the positioning station displacing a fastener in the positioning station; and

fastener supply means adapted to position and hold a fastener in the positioning station in the driverhousing for each operation of the impact tool. 2. The impact tool of claim 1 wherein the fifth leg member is attached to and extending downward from the fastener supply means. 

1. An impact tool for driving fasteners through a workpiece into masonry surfaces or the like including: a driver housing having means to locate a workpiece in a position to receive a fastener above the workpiece and means to align the impact tool so that a fastener in the positioning station is substantially perpendicular to the surface into which the fastener is to be driven, including four leg members extending downward from the driver housing in a position to straddle the workpiece and a fifth leg member remote from the driver housing to provide stability; a driver positioned in the driver housing immediately above the fastener positioning station and movable downward through the fastener positioning station; means to impact the driver with a velocity sufficient to force the driver downward through the positioning station displacing a fastener in the positioning station; and fastener supply means adapted to position and hold a fastener in the pOsitioning station in the driver housing for each operation of the impact tool.
 2. The impact tool of claim 1 wherein the fifth leg member is attached to and extending downward from the fastener supply means. 